directive @core(feature: String!) repeatable on SCHEMA

directive @join__owner(graph: join__Graph!) on OBJECT

directive @join__type(
    graph: join__Graph!
    key: String!
    resolvable: Boolean = true
) repeatable on OBJECT | INTERFACE

directive @join__field(
    graph: join__Graph
    requires: String
    provides: String
) on FIELD_DEFINITION

directive @join__graph(name: String!, url: String!) on ENUM_VALUE

enum join__Graph {
    PRODUCTS @join__graph(name: "products", url: "http://example.com/products")
    USERS @join__graph(name: "users", url: "http://example.com/users")
}

type Product
    @join__type(graph: PRODUCTS, key: "id")
{
    id: ID!
    name: String @join__field(graph: PRODUCTS)
    reviews: [Review] @join__field(graph: PRODUCTS)
}

type Review
    @join__type(graph: PRODUCTS, key: "id")
{
    author: User @join__field(graph: PRODUCTS, provides: "name")
    content: String @join__field(graph: PRODUCTS)
    id: ID!
}

type User
    @join__type(graph: PRODUCTS, key: "id")
    @join__type(graph: USERS, key: "id")
{
    email: String @join__field(graph: USERS)
    id: ID!
    name: String @join__field(graph: USERS)
}

type Query {
    product(id: ID!): Product @join__field(graph: PRODUCTS)
    user(id: ID!): User @join__field(graph: USERS)
}